An all-season pneumatic tire is regarded as one which currently qualifies for a mud and snow (M&S) service rating under the criteria for such rating established by the Rubber Manufacturing Association, Akron, Ohio. In general, such rating requires that the tire tread have grooves of depth at the lateral edges that are substantially equal to the average groove depth in the vicinity of the mid-circumferential plane, are angled laterally toward the respective lateral (axial) edges of the tread for at least one-half inch, and such grooves are required to have a width of at least 0.060 inch at the tread surface. All-season tires are characterized by grooves that define blocks, and sometimes one or more ribs, in the tread surface. This results in a more aggressive appearance than that of a more conventional fully-ribbed tire, and provides improved traction characteristics in snow and under wet conditions as compared to the conventional ribbed tire. All-season tires are distinguished from snow tires in that, while both are required to satisfy all Federal Motor Vehicle Safety Standard 109 tests applicable to passenger tires in general, snow tires are exempt from the tire grade labelling standards.
On the other hand, high-performance tires are not subject to an industry standard definition. High-performance tires are generally understood to be characterized as having an aspect ratio (hereinafter defined) that is equal to or less than 70 percent. High-performance tires also have high traction on dry and wet pavement, stiff cornering characteristics, and in some cases have H or V speed ratings, such ratings being based on a system originally established in Europe. A high-performance passenger pneumatic tire typically possesses an aggressive and ornamental tread design that, as is the case with many all-season tires, typically is of a block-type pattern. In the high-performance tire, stiffness at the tread shoulder is desirable for its cornering characteristics, but can present problems with heat buildup, particularly in speed-rated tires. In contrast to all-season tires, the typical high-performance tire, for reasons of both rubber compounding and mechanical design, does not yield desired performance in cold weather and does not possess desirable mud and snow traction characteristics.
The modern radial-ply pneumatic tire is designed under standards promulgated by any of several organizations, including The Tire & Rim Association, Inc., The European Tyre & Rim Technical Organisation and the Japan Automobile Tire Manufacturers Association. Under the standards of these organizations, which are quite similar, when a tire of a given size is being designed, it is designed for mounting on a "design rim," which is a rim having a specified configuration and width. The "design rim width" is the specific rim width assigned to each tire size and typically is equal to 70 percent of the specific tire's "section width." The "section width" is the width of the new tire, including 24-hour inflation growth and including normal sidewalls, but not including protective side ribs, bars or decorations. The "section height" of the tire is equal to the radial distance from the nominal rim diameter to the outer diameter of the tire at its mid-circumferential plane. The "aspect ratio" of the tire is the ratio of its section height to its section width. The "tire design load" is the base or reference load assigned to a tire at a specific inflation pressure and service condition; other load-pressure relationships applicable to the tire are based on that base or reference load. The terms "normal inflation pressure" and "normal load" as used herein refer respectively to the specific inflation pressure and load assigned by the appropriate standards organization for the design load as defined above for the service condition of the tire.